A device used to switch electrical current at a selectable setpoint temperature.

In Jeffreys' classification, a wind for which the pressure force exactly balances the viscous force, in which the vertical transfers of momentum predominate.

Same as parhelion.

Phase Shift Keying. A form of phase modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

A graphical device used for the determination of the speed of the geostrophic wind from the isobar or contour-line spacing on a synoptic chart.

Operation mode of a communication circuit in which one end can only transmit and the other end can only receive.

Generally, a measure of the departure of the mean daily temperature from a given standard, one degree day for each degree (

A very sensitive electrostatic electrometer for measuring small potential differences.

An effect noted primarily in wet snow conditions when snow clings to the sides of a precipitation gauge and gradually accumulates until the gauge orifice is capped with accumulated snow. This effect can be minimized by using large collectors, and wind scr ...

A rain gauge or array of rain gauges designed to measure the inclination and direction of falling rain.

The elevation of the water surface in a stream as measured by a river gauge with reference to some arbitrarily selected zero datum.

An instrument for taking photographs of an image of the sun in monochromatic light.

One of several constant-pressure levels in the atmosphere for which a complete evaluation of data derived from upper air observations is required.

Literally "not wet", containing no liquid.

A form of psychrometer with wet-bulb and dry-bulb thermometers mounted on opposite sides of a specialty designed graph of the psychrometric tables. It is so arranged that the intersections of two curves determined by the wet-bulb and dry-bulb readings -yi ...

The inaccuracy that the manufacturer permits when the unit is calibrated in the factory.

General name for an instrument which measures the earth's magnetic field intensity.

Apparatus from which the nature and time of precipitation may be determined.

Facing away from the wind.

The state of the weather with respect to its effect upon the kindling and spreading of forest fires.